This invention relates to the housing (volute) surrounding a centrifugal blower or fan.
Centrifugal blowers and fans generally include an impeller that rotates in a predetermined direction in a housing and is driven by a motor. Such blowers are used in a variety of applications where energy consumption, efficiency, noise, and space constraints are important. Various prior housing designs have attempted to meet predetermined space constraints while maintaining the desired performance.
Generally, a volute may be included around the circumference of a centrifugal fan to accumulate the flow generated by the impeller, particularly for fans with backward curved impeller blades. Volutes add substantially to the overall blower package size, forcing a tradeoff of increased efficiency from the volute aerodynamics, on the one hand, versus reduced motor and impeller size, resulting in increased energy consumption and noise on the other.
Japanese patent (#52-86554) describes a housing or volute which expands with angle in the axial direction.
U.S. Pat. No. 3,246,834 describes a housing which expands significantly in the axial direction.
In many instances, the blower must be accommodated in a space that includes significant discontinuities, e.g. due to packaging constraints from other equipment. Specifically, for automobile blowers positioned in tightly configured spaces, such discontinuities are common.